“It’s a good thing you’re going underground,” our bus driver calls out as his windshield wipers work furiously to bat away the rain. I watch the drops race across my window, blurring the moss-covered lava field that surrounds us. We are headed thirty minutes southeast of Reykjavík, with the intent of entering the chamber of a dormant volcano that erupted 4,000 years ago. We are about to go into the abyss.